Route reliability record
SAN→DTW
San Diego to Detroit
- Flights
- 1,314
- Period
- July 2025 to June 2026
- Distance
- 1,956 mi
- Carriers
- 2
This route earns an A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.6%. When something does go wrong the average delay runs about 50 minutes. That rests on 1,314 SAN to DTW flights, with a median arrival 7 minutes early.
Best time to fly SAN to DTW: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 91.2% of the time and Tuesday flights 92.1%, against 85.8% for the route overall.
Set against the rest of the country, this route's record is 8 points better than the US average of 77.6%. That gap is worth roughly 82 fewer late arrivals for every thousand flights.
Key figures
On time
85.8%
Arrivals under 15 minutes late, of 1,299 completed flights
Avg delay
50 min
Across delayed arrivals only, not all flights
Cancelled
1.07%
National rate is 1.81%
Best carrier
Delta
86.4% on time across 1,260 flights
These figures cover 1,314 flights between July 2025 and June 2026. The median arrival is 7 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Carrier by carrier
Which airline is most reliable on SAN to DTW
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 1,260 | 86.4% | 50 min | 1.03% | A |
| Spirit Airlinesthin sample | 54 | 71.7% | 52 min | 1.85% | C |
Flight by flight
Flights on SAN to DTW
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 13 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am365 flights91.2%
- 8am–11am—
- 11am–2pm418 flights78.4%
- 2pm–5pm185 flights84.2%
- 5pm–8pm—
- 8pm–5am346 flights90.0%
Scale runs 70% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 78.4% on time against 91.2% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 418 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 16 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
October is the best month on the calendar at 93.2% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 133 flights.
Across the week, Tuesday is the strongest day at 92.1% on time and Saturday the weakest at 83.2%. 9 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 9,136 reported delay minutes.
- 35%Carrier
- 33%Late-arriving aircraft
- 32%National Airspace System
- 0%Extreme weather
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 3,170 of the 9,136 delay minutes reported here. The split is drawn from 9,136 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.2% on time here.
Cancellations sit at 1.07% against a national 1.81%, which is ordinary. Diversions add another 0.08%.
Connections and stage length
What a delay here actually costs
Badly late arrivals are rare here: only 2.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
At 1,956 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 75.4% on time across 1,314 flights, 10 points below this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 10 points of difference.
The sample behind these figures is 1,314 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.
Work out the risk of missing a connection in DTW after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 93.2% on time and March 76.9%, a swing of 16 points. If the dates move at all, move them out of March before you think about anything else. 1,299 completed flights over 12 months sit behind that.
Common questions
SAN to DTW questions
How often is SAN to DTW delayed?
About one flight in seven arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.2% of the 1,314 flights in this analysis, against 22.4% nationally. Delayed flights are late by about 50 minutes on average.
How reliable is SAN to DTW compared with the rest of the country?
85.8% of flights arrive on time here against a national 77.6%, a difference of 8 points in its favour. That is worth a A on this site's grading scale.
What time of day has the fewest delays on SAN to DTW?
The 5am–8am departure window is the strongest at 91.2% on time. The 11am–2pm window is the weakest at 78.4%, 13 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are March delays on SAN to DTW?
March is the weakest month at 76.9% on time, compared with 93.2% in October. Across the year that is 16 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- DTW to SAN — the return legseparate record
- San Diego International (SAN) delay statistics
- Detroit Metropolitan Wayne County (DTW) delay statistics
- SAN to SFO, a related route65.0%
- ORD to DTW, a related route70.6%
- SAN to DEN, a related route79.2%
- Delta Air Lines on-time record86.4%
- Spirit Airlines on-time record71.7%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. SAN to DTW and DTW to SAN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.